Polyparabanic acid derivatives

ABSTRACT

New polyparabanic acid derivatives and their production by reacting Δ 2  -imidazolines with organic polyisocyanates.

This invention relates to polyparabanic acid derivatives and to aprocess for their preparation.

Polyparabanic acid derivatives according to the invention contain thestructural unit represented by the following formula (I) ##STR1##repeated in the molecule, preferably from 2-100 times. In the aboveformula (I)

R¹, r⁶, r⁷ and R⁸ may be the same or different and each represents anoptionally substituted aliphatic, aromatic or aliphatic-aromatic groupand

R², r³, r⁴ and R⁵ may be the same or different and each representshydrogen or an optionally substituted aliphatic, aromatic oraliphatic-aromatic group. The repeating units represented by formula (I)are linked by the groups, R⁶ and/or R⁷ and/or R⁸.

The monofunctional, difuctional or polyfunctional radicals R⁶, R⁷ and R⁸are preferably derived from optionally substituted aliphatic radicalshaving from 2-20, preferably from 2-12 C-atoms, e.g. alkyl radicalshaving from 2-12 C-atoms, optionally substituted aromatic radicalshaving from 6-20, preferably from 6-16 C-atoms, e.g. aryl radicalshaving up to 20 carbon atoms, such as phenyl, naphthyl, diphenyl ordiaryl ether radicals, radicals derived from alkyl or aryl esters oforganic or inorganic acids, or optionally substituted aliphatic-aromaticradicals having from 7-20 C-atoms, e.g. xylidene.

R², R³, R⁴ and R⁵ are preferably hydrogen or derived from optionallysubstituted aliphatic radicals having from 1-20, preferably from 1-12C-atoms, e.g. alkyl radicals having from 1-6 carbon atoms, cycloalkylenegroups having from 5-7 carbon atoms, optionally substituted aromaticradicals having from 6-20, preferably from 6-16 C-atoms, e.g. arylgroups such as phenyl, naphthyl, diphenyl or diphenyl ether groups, oroptionally substituted aliphatic-aromatic radicals having from 7-20C-atoms, e.g. benzyl. R² and R³ or R⁴ and R⁵ may also be joined togetherto form a cycloaliphatic ring.

R¹ is derived from an optionally substituted aliphatic radical havingfrom 1-20, preferably from 1-12 C-atoms, e.g. from an alkyl radicalhaving from 1-6 carbon atoms, cycloalkyl radical having from 5-7 carbonatoms in the ring, an optionally substituted aromatic radical havingfrom 6-20, preferably from 6-16, carbon atoms, e.g. aryl groups such asphenyl, naphthyl, diphenyl or diphenyl ether groups, or an optionallysubstituted aliphatic-aromatic radical having from 7-20 C-atoms, e.g.benzyl radical.

The following are examples of possible substituents of the abovementioned aliphatic, aliphatic-aromatic or aromatic radicals: C₆ -C₁₆aryl groups (preferably phenyl), OH, aldehyde and ketone groups, CN,NO₂, alkylmercapto and alkoxy groups preferably having from 1-4 C-atoms,carboxylic acid ester groups, phosphonic acid ester groups, phosphinicacid ester groups and sulphonic acid ester groups, preferably thoseobtained from lower aliphatic alcohols, particularly alcohols havingfrom 1-8, more particularly from 1-4 C-atoms; a disubstituted aminogroup, a disubstituted carboxamide group and a disubstitutedsulphonamide group, preferably substituted by lower aliphatic groups(preferably with 1-4 C-atoms), halogens (preferably fluorine, chlorine,or bromine), lower haloalkyl groups (preferably having from 1-4 C-atomsand preferably containing fluorine and/or chlorine) and, in the case ofaromatic and heterocyclic radicals, the substituents may also be loweralkyl groups, preferably with 1-4 C-atoms.

The polyparabanic acid derivatives according to the invention preferablyhave molecular weights of from 1000-50,000, in particular from4000-30,000 (determined by the osmotic method). They show characteristicIR absorption bands at 1720-1740 cm⁻¹ (strong) and 1770-1800 cm⁻¹ (weak)in addition to urea carbonyl bands at 1630-1700 cm⁻¹ (strong).

A further object of the present invention is a process for theproduction of the inventive polyparabanic acid derivatives by reactingΔ² -imidazolines corresponding to the following general formula (II)##STR2## wherein R¹ to R⁵ are as defined above, with organicpolyisocyanates.

The following Δ² -imidazolines are preferably used for carrying out theprocess:

1-methyl-Δ² -imidazoline;

1-ethyl-Δ² -imidazoline;

1-isopropyl-Δ² -imidazoline;

1-n-butyl-Δ² -imidazoline;

1-cyclohexyl-Δ² -imidazoline;

1-benzyl-Δ² -imidazoline;

1-phenyl-Δ² -imidazoline;

1,4-dimethyl-Δ² -imidazoline;

1-n-butyl-4-methyl-Δ² -imidazoline;

1-benzyl-5-ethyl-Δ² -imidazoline;

1,4-diphenyl-Δ² -imidazoline;

N-(n-butyl)-hexahydrobenzimidazole;

1-cyanoethyl-Δ² -imidazoline;

3-[1-(2-imidazolinyl)]-propionic acid methyl ester;

3-[1-(2-imidazolinyl)]-propionic acid ethyl ester;

2-[1-(2-imidazolinyl)]-ethylphosphonic acid dimethyl ester;

2-[1-(2-imidazolinyl)]-ethylphosphonic acid diethyl ester;

1-(2-hydroxyethyl)-Δ² -imidazoline;

1-[3-(3,5-dihydrothiphene-S-dioxid-yl)]-Δ² -imidazoline;

1-phenyl-4,4-dimethyl-Δ² -imidazoline; and

1-methoxycarbonylethyl-hexahydrobenzimidazole

Organic polyisocyanates for the purpose of the present invention areorganic isocyanates having at least two isocyanate groups per molecule.

The polyisocyanates used as starting components according to the presentinvention may be aliphatic isocyanates having from 2-20 C-atoms,cycloaliphatic isocyanates having from 5-12 C-atoms, arylaliphaticisocyanates having from 7-20 C-atoms, aromatic isocyanates having from6-20 C-atoms, and heterocyclic isocyanates having from 4-20 C-atoms, forexample the polyisocyanates described by W. Siefken in Justus LiebigsAnnalen der Chemie, 562 pages 75 to 136. The following are specificexamples: ethylene diisocyanate, 1,4-tetramethylene diisocyanate,1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate,cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and 1,4-diisocyanate andany mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (German Auslegeschrift No. 1,202,785), 2,4- and2,6-hexahydrotolylene diisocyanate and any mixtures of these isomers,hexahydro-1,3- and/or 1,4-phenylene diisocyanate, perhydro-2,4'- and/or-4,4'-diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate,2,4- and 2,6-tolylene diisocyanate and any mixtures of these isomers,diphenylmethane-2,4'- and/or -4,4'-diisocyanate,naphthylene-1,5-diisocyanate, triphenylmethane-4,4',4"-triisocyanate,polyphenyl-polymethylene polyisocyanate obtainable byaniline-formaldehyde condensation followed by phosgenation, for examplethe compounds described in British Pat. Nos. 874,430 and 848,671,perchlorinated aryl polyisocyanates such as those described in GermanAuslegeschrift No. 1,157,601, polyisocyanates containing carbodiimidegroups as described in German Pat. No. 1,092,007, the diisocyanatesdescribed in U.S. Pat. No. 3,492,330, polyisocyanates containingallophanate groups, e.g. as described in British Pat. No. 994,890,Belgian Pat. No. 761,626 and published Dutch Patent Application No.7,102,524, polyisocyanates containing isocyanurate groups as described,for example, in German Pat. Nos. 1,022,789, 1,222,067 and 1,027,394 andin German Offenlegungsschrift Nos. 1,929,034 and 2,004,048,polyisocyanates containing urethane groups, e.g. as described in BelgianPat. No. 752,261 or in U.S. Pat. No. 3,394,164, polyisocyanatescontaining acylated urea groups according to German Pat. No. 1,230,778,polyisocyanates containing biuret groups, e.g. as described in GermanPat. No. 1,101,394, in British Pat. No. 889,050 and in French Pat. No.7,017,514, polyisocyanates prepared by telomerisation reactions, e.g. asdescribed in Belgian Pat. No. 723,640, polyisocyanates containing estergroups, e.g. the compounds mentioned in British Pat. Nos. 956,474 and1,072,956, U.S. Pat. No. 3,567,763 and German Pat. No. 1,231,688, andreaction products of the above mentioned isocyanates with acetalsaccording to German Pat. No. 1,072,385.

The distillation residues obtained from the commercial production ofisocyanates which still contain isocyanate groups may also be used,optionally in the form of solutions in one or more of the abovementioned polyisocyanates. Any mixtures of the above mentionedpolyisocyanates may also be used.

As a rule, it is particularly preferred to use commercially readilyavailable polyisocyanates such as 2,4- and 2,6-tolylene diisocyanate andany mixtures of these isomers ("TDI"), polyphenyl-polymethylenepolyisocyanates which are obtained by aniline-formaldehyde condensationfollowed by phosgenation ("crude MDI") and polyisocyanates containingcarbodiimide, urethane, allophanate, isocyanurate, urea or biuret groups("modified polyisocyanates").

Aliphatic or aromatic monoisocyanates may be used in addition topolyisocyanates to reduce the degree of cross linking of thepolyparabanic acid derivatives.

The process is preferably carried out by reacting the starting materialsin an organic solvent at temperatures of from -20° to 400° C. Thepolymer produced by the reaction either stays in solution orprecipitates. It may be isolated by distillation of the solvent. Thequantities of the starting materials may be chosen to provide 0.5 to 10mol, preferably about 3 mol of isocyanate groups per mol of Δ²-imidazoline. Solvents suitable for the process are compounds which areinert towards isocyanate groups, for example aromatic hydrocarbons,chlorinated aromatic hydrocarbons, benzonitrile, aliphatic hydrocarbons,esters and ketones. Particularly preferred are toluene, xylene,mesitylene, chlorobenzene, dichlorobenzene, N-methyl pyrrolidone,dimethylformamide, dimethylacetamide, hexamethyl phosphoric acidtriamide, tetramethyl urea, nitromethane and nitrobenzene. The compoundsmay, however, be reacted without solvents.

The reaction times are generally from 15 minutes to 100 hours,preferably from 30 minutes to 20 hours, but may lie above or below theselimits in special cases.

Reaction temperatures from -20° to 400° C are employed, depending on theparticular starting materials. Temperatures from 60° to 350° C arepreferred, particularly from 80° to 250° C.

Polymerisation may be carried out with the aid of the usual acid orbasic catalysts, e.g. metal alcoholates or tertiary amines.

The polyparabanic acid derivatives obtained may carry isocyanate endgroups so that they can be cross linked with the usual substances usedin isocyanate chemistry, such as polyols or polyamines or they may becross linked to form isocyanurate structures. Chain lengthening withformation of carbodiimide or uretdione structures is also possible.

Other polymers may also be included in the process of the presentinvention in known manner, for example polyesters, polyethers,polyamides, polyurethanes, polyolefins, polyacetals, polyepoxides,polyimides, polyamidines, polyimide diisocyanates, and polyhydantoins.These polymers may be added to the finished inventive polymers or theymay be copolymerized with them.

According to one special embodiment of the process, polyesters orpolyethers containing hydroxyl groups are also added and excessquantities of isocyanate components are used. This results in theformation of a combination of parabanic acid and urethane. For thispurpose, mixtures of, for example, polyhydroxyl compounds,polyisocyanates or derivatives thereof and a compound of the generalformula (II) are converted simultaneously in a final step of the processinto the synthetic resin, optionally after precondensation of two ofthese components.

The hydroxyl polyesters used are commonly known and obtained in theusual manner from polycarboxylic acids such as succinic, adipic,sebacic, phthalic, isophthalic, terephthalic or oleic acids andpolyhydric alcohols such as glycol, diethylene glycol, triethyleneglycol, propylene glycol, dipropylene glycol, glycerol,trimethylolpropane or pentaerythritol.

The polyparabanic acid derivatives according to the invention andmixtures thereof with other polymers are temperature resistant syntheticresins which have excellent mechanical properties and may be used aslacquers and foils, etc. They may contain the usual additives used forsynthetic resins, such as fillers, pigments, anti-oxidants andplasticisers.

EXAMPLE 1

17.4 parts by weight of 2,4-tolylene diisocyanate were added dropwise to6.3 parts by weight of 1-(n-butyl)-Δ² -imidiazoline in 20 parts byweight of dichlorobenzene at 30° C over a period of 1 hour. The reactionmixture was then stirred at 160° C for 1 hour. 18.0 parts by weight of asolid polymer were obtained after filtration. This polymer has thecharacteristic IR absorption bands for parabanic acid derivatives at1787 cm⁻¹ (weak) and 1729 cm⁻¹ (strong).

EXAMPLE 2

12.3 parts by weight of 1-cyanoethyl-Δ² -imidazoline were added dropwiseto 26.1 parts by weight of an isomeric mixture of 80 parts of2,4-tolylene diisocyanate and 20 parts of 2,6-tolylene diisocyanate in40 parts by weight of dimethylformamide at 60° C within a period of 1hour. The reaction mixture was then stirred for 1 hour at 100° C. 38parts by weight of a solid polymer were obtained after filtration.Viscosity of a 38% solution in m-cresol at 25° C: 23280 cP.

EXAMPLE 3

4.0 parts by weight of 1-benzyl-Δ² -imidazoline and 12.2 parts by weightof diphenylmethane-diisocyanate-(4,4') were stirred into 20 parts byweight of toluene at 110° C over 30 minutes. 13.6 parts by weight of asolid polymer were obtained by filtration. The polymer has thecharacteristic IR absorption bands for parabanic acid derivatives at1788 cm⁻¹ (weak) and 1730 cm⁻¹ (strong).

EXAMPLE 4

7,8 parts by weight of 3-[1-(2-imidazolinyl)]-propionic acid methylester were added dropwise within 1 hour to 17.4 parts by weight of2,4-tolylene diisocyanate in 20 parts by weight of toluene at 100° C.24.6 parts by weight of a solid polymer were obtained after filtration.Viscosity of a 33% solution in cresol at 25° C: 3360 cP.

EXAMPLE 5

12.3 parts by weight of 1-cyanoethyl-Δ² -imidazoline were added dropwiseto 44.4 parts by weight of isophorone diisocyanate within 1 hour at 100°C. The reaction mixture was then stirred for 1 hour at 150° C. Afterdehydration under vacuum, 50.2 parts by weight of a solid polymercontaining isocyanate groups were obtained. The polymer had thecharacteristic IR absorption bands for parabanic acid derivatives at1777 cm⁻¹ (weak) and 1718 cm⁻¹ (strong). Viscosity of a 33% solution incresol at 25° C: 11040 cP.

EXAMPLE 6

5.7 parts by weight of 1-(2-hydroxyethyl)-Δ² -imidazoline in 30 parts byweight of chloroform were added dropwise to 22.2 parts by weight ofisophorone diisocyanate within 1 hour at 60° C. The resulting solutionwas evaporated under vacuum and dried. 27.1 parts by weight of a solidpolymer having the characteristic IR absorption bands for parabanic acidderivatives at 1776 cm⁻¹ and 1728 cm⁻¹ (strong) were obtained. Averagemolecular weight determined by the GPC method in tetrahydrofuran: 1850.

EXAMPLE 7

5.9 parts by weight of 2,5-dihydrothiophene-S-dioxide in 60 parts byweight of chloroform were added dropwise to 3.5 parts by weight of Δ²-imidazoline at 50° C within 1 hour. The reaction mixture was thenstirred for 30 minutes at 60° C and 12.6 parts by weight of 2,4-tolylenediisocyanate were then added dropwise at this temperature over a periodof 30 minutes. The reaction mixture was then stirred for 1 hour at 60°C. 16.9 parts by weight of a solid polymer were obtained afterfiltration and drying under vacuum. Viscosity of a 33% solution inN-methyl pyrolidone at 25° C: 140 cP.

EXAMPLE 8

6.8 parts by weight of vinyl phosphonic acid dimethyl ester were addeddropwise within 1 hour to a suspension of 3.5 parts by weight of Δ²-imidazoline in 10 parts by weight of toluene at room temperature. 26.1parts by weight of an isomeric mixture of 80 parts by weight of2,4-tolylene diisocyanate and 20 parts by weight of 2,6-tolylenediisocyanate in 10 parts by weight of toluene were then added dropwiseover a period of 6 hours. The solution was heated to 110° C for 10minutes. 28.9 parts by weight of a solid polymer were therebyprecipitated. The polymer was suction filtered and dried under vacuum.

EXAMPLE 9

15.6 parts by weight of 3-[1-(2-imidazolinyl)]-propionic acid methylester were added dropwise to 134.4 parts by weight of hexamethylenediisocyanate within 1 hour at 80° C. Stirring was continued for 1 morehour at 80° C. Evaporation of the solution under a high vacuum at 150° Cyielded 66 parts by weight of a prepolymer containing 14.2% ofisocyanate groups. Viscosity of a 75% solution in ethylene glycolmonomethyl ether acetate at 25° C: 2400 cP.

50 parts by weight of this 75% solution of the prepolymer were mixedwith 40 parts by weight of a 65% solution in ethyl glycol acetate of apolyester which had been prepared from 52 parts by weight of phthalicacid anhydride, 0.6 parts by weight of maleic acid anhydride and 54parts by weight of trimethylol propane and contained 5.2% of hydroxylgroups, and 0.1 part by weight of Sn(II) dioctoate. A quick dryinglacquer was obtained.

EXAMPLE 10

8.7 parts by weight of 4,4-dimethyl-1-phenyl-Δ² -imidazoline were addeddropwise within 1 hour to 12.6 parts by weight of hexamethylenediisocyanate in 30 parts by weight of chloroform at 60° C. When thesolution was concentrated by evaporation under vacuum, 18.1 parts byweight of a solid polymer which had the characteristic IR absorptionbands for parabanic acid derivatives at 1779 cm⁻¹ (weak) and 1722 cm⁻¹(strong) were obtained.

What is claimed is:
 1. Polyparabanic acid derivatives which contain thefollowing recurring structural unit from 2 to 100 times ##STR3## whereinR¹, R⁶, R⁷ and R⁸ may be the same or different, and each represents anoptionally substituted aliphatic, aliphatic-aromatic or aromaticradical, and R², R³, R⁴ and R⁵ may be the same or different, and eachrepresents hydrogen or an optionally substituted aliphatic,aliphatic-aromatic or aromatic radical.
 2. Polyparabanic acidderivatives as claimed in claim 1 which have a molecular weight of from1,000 to 50,000.
 3. Polyparabanic acid derivatives as claimed in claim1, wherein R¹, R⁶, R⁷ and R⁸ may be the same or different, and each isan optionally substituted aliphatic radical containing from 2 to 20carbon atoms or an optionally substituted aromatic radical containing 6to 20 carbon atoms and R², R³ R⁴ and R⁵ may be the same or different andare each hydrogen or one of said moieties defining R¹, R⁶, R⁷ and R⁸. 4.A process for the preparation of polyparabanic acid derivatives asclaimed in claim 1 wherein a Δ² -imidazoline of the formula ##STR4##wherein R¹ to R⁵ are as defined in claim 1 is reacted with an organicpolyisocyanate at a temperature of from -20° to 400° C.
 5. A process asclaimed in claim 4 wherein the reaction is carried out at a temperatureof from 60° to 350° C.
 6. A process as claimed in claim 5 wherein thereaction is carried out at a temperature of from 80° to 250° C.
 7. Aprocess as claimed in claim 4 wherein the reaction is carried out usingfrom 0.5 to 10 moles of isocyanate per mole of Δ² -imidazoline.